Efficacy of MAVIG X-Ray Protective Drapes in Reducing CTO Operator Radiation

Background. The MAVIG X-ray protective drape (MXPD) has been shown to reduce operator radiation dose during percutaneous coronary interventions (PCI). Whether MXPDs are also effective in reducing operator radiation during chronic total occlusion (CTO) PCI, often with dual access, is unknown. Methods. We performed a prospective, randomized-controlled study comparing operator radiation dose during CTO PCI (n = 60) with or without pelvic MXPDs. The primary outcomes were the difference in first operator radiation dose (μSv) and relative dose of the first operator (radiation dose normalized for dose area product) at the level of the chest in the two groups. The effectiveness of MXPD in CTO PCI was compared with non-CTO PCI using a patient-level pooled analysis with a previously published non-CTO PCI randomized study. Results. The use of the MXPD was associated with a 37% reduction in operator dose (weighted median dose 26.0 (IQR 10.00–29.47) μSv in the drape group versus 41.8 (IQR 30.82–60.59) μSv in the no drape group; P < 0.001 ) and a 60% reduction in relative operator dose (median dose 3.5 (IQR 2.5–5.4) E/DAPx10−3 in the drape group versus 8.6 (IQR 4.2–12.5) E/DAPx10−3 in the no drape group; P = 0.001 ). MXPD was equally effective in reducing operator dose in CTO PCI compared with non-CTO PCI ( P value for interaction 0.963). Conclusions. The pelvic MAVIG X-ray protective drape significantly reduced CTO operator radiation dose. This trial is clinically registered with https://www.clinicaltrials.gov (unique identifier: NCT04285944).

Integrity of personal radiation protective equipment (PRPE): a 3-year longitudinal follow-up study

Background Personal radiation protective equipment (PRPE) such as lead aprons, vests, skirts and thyroid shields minimize radiation exposure of operators using ionizing radiation. However, PRPE might be prone to cracks and tears in the attenuating layer of the garments which results in inadequate radiation protection and increased operator dose. Currently, there are no uniform guidelines regarding regular inspection and/or rejection criteria of PRPE. Purpose This study aims to investigate the prevalence, qualification and quantification of PRPE integrity during a longitudinal follow-up. Methods All PRPE of a large, general hospital was yearly evaluated in the period 2018–2020. The equipment was inspected on a tele-operated X-ray table and cracks and tears were qualified and quantified using an X-ray opaque ruler. Rejection criteria of Lambert & McKeon were applied to accept or reject further use of the PRPE. In brief, all pieces, except for thyroid shields, with a total defect area larger than 670mm2 are rejected. For tears, specifically at the position of the gonads, an extra rejection criterion of 15mm2 is defined. For thyroid shields, the rejection criterion is set to 11mm2. Results In the 3-year follow-up period, a total of 915 PRPE were evaluated. 43.3% of PRPE showed tears and 29.3% needed to be rejected based on the Lambert & McKeon criteria. More specifically, in 2018, 2019 and 2020, respectively, 17.4%, 16.9% and 21.2% were rejected. In the attached figure, typical examples of visualized defects are represented. The median tear area (interquartile range) was 12 (30) mm2. Remarkably, of 195 newly registered PRPE, 8.7% showed tears in the first year of use of which 88.2% needed to be rejected. In the latter case, the median tear area (interquartile range) was 40 (50) mm2. Information regarding purchase date and size is missing in respectively 45.5% and 50.7% of the cases. Additionally, 13.7% lacked information regarding lead equivalency. Conclusion PRPE are prone to tears and cracks. Up to 40% of PRPE showed tears and cracks resulting in nearly 20% rejections. Newly purchased PRPE are not guaranteed to remain free of cracks and tears in the first year of use. These results urge the importance for regular X-ray based integrity analysis of PRPE. FUNDunding Acknowledgement Type of funding sources: None.

Radiation Awareness for Endovascular Abdominal Aortic Aneurysm Repair in the Hybrid Operating Room: An Instant Operator Risk Chart for Daily Practice

Introduction: While the operator radiation dose rates are correlated to patient radiation dose rates, discrepancies may exist in the effect size of each individual radiation dose predictors. An operator dose rate prediction model was developed, compared with the patient dose rate prediction model, and converted to an instant operator risk chart. Materials and Methods: The radiation dose rates (DRoperator for the operator and DRpatient for the patient) from 12,865 abdomen X-ray acquisitions were selected from 50 unique patients undergoing standard or complex endovascular aortic repair (EVAR) in the hybrid operating room with a fixed C-arm. The radiation dose rates were analyzed using a log-linear multivariable mixed model (with the patient as the random effect) and incorporated varying (patient and C-arm) radiation dose predictors combined with the vascular access site. The operator dose rate models were used to predict the expected radiation exposure duration until an operator may be at risk to reach the 20 mSv year dose limit. The dose rate prediction models were translated into an instant operator radiation risk chart. Results: In the multivariate patient and operator fluoroscopy dose rate models, lower DRoperator than DRpatient effect size was found for radiation protocol (2.06 for patient vs 1.4 for operator changing from low to medium protocol) and C-arm angulation. Comparable effect sizes for both DRoperator and DRpatient were found for body mass index (1.25 for patient and 1.27 for the operator) and irradiated field. A higher effect size for the DRoperator than DRpatient was found for C-arm rotation (1.24 for the patient vs 1.69 for the operator) and exchanging from femoral access site to brachial access (1.05 for patient vs 2.5 for the operator). Operators may reach their yearly 20 mSv year dose limit after 941 minutes from the femoral access vs 358 minutes of digital subtraction angiography radiation from the brachial access. Conclusion: The operator dose rates were correlated to patient dose rate; however, C-arm angulation and changing from femoral to brachial vascular access site may disproportionally increase the operator radiation risk compared with the patient radiation risk. An instant risk chart may improve operator dose awareness during EVAR.

The radioprotective effect of the cathpax air cabin during interventional cardiology procedures

Funding Acknowledgements Type of funding sources: Public hospital(s). Main funding source(s): Hospital Puerta del Mar BACKGROUND The use of ionizing radiation during cardiac catheterization interventions adversely impacts both the patients and the medical staff. Traditional radiation protection equipment is only partially effective. The Cathpax® radiation protection cabin (RPC) has demonstrated to significantly reduce radiation exposure in electrophysiological and neuroradiology interventions. Our objective was to analyze whether the Cathpax® RPC reduces radiation dose in coronary and cardiac structural interventions in unselected real-world procedures. METHODS AND RESULTS In this non-randomized all-comers prospective study, 119 consecutive cardiac interventional procedures were alternatively divided into two groups: the RPC group (n = 59) and the non-RPC group (n = 60). No significant changes in patients and procedures characteristics, average contrast volume, air kerma (AK), dose area-product (PDA) and fluoroscopy time between both groups were apparent. In RPC group, the first operator relative radiation exposure was reduced by 78% at the chest and by 70% at the wrist. This effect was consistent during different types of procedures including complex percutaneous interventions and structural procedures. CONCLUSIONS Our study demonstrates, for the first time, that the Cathpax® cabin significantly and efficiently reduces relative operator radiation exposure during different types of interventional procedures, confirming its feasibility in a real-world setting. Table 3.Comparison of radiation exposureStructural (n = 12)Coronary (n = 107)pPrimary outcomesFirst operator relative exposure at chest*6.8 ± 33 ± 0.60.06First operator relative exposure at left wrist*19.3 ± 104 ± 1.50.01Secondary outcomesSecond operator relative exposure at chest*2.5 ± 1.21.2 ± 0.20.06First operator dose at chest (E in µSv)59.2 ± 4317.2 ± 50.08First operator dose at left wrist (E in µSv)134.1 ± 9623.4 ± 90.04Second operator dose at chest (E in µSv)19 ± 165.7 ± 20.1Patient exposure (DAP in mGy·cm2)62651 ± 2618059682 ± 142860.8Fluoroscopy time, min (±SD)24.2 ± 715.7 ± 40.2Abstract Figures 1 and 2

Primary operator radiation dose in the cardiac catheter laboratory

Objectives: Radiation from cardiac angiography procedures is harmful to patients and the staff performing them. This study sought to investigate operator radiation dose for a range of procedures and different operators in order to investigate trends and optimise dose. Methods: Real-time dosemeters (RTDs) were worn by operators for angiography procedures for 3 years. Dose–area product (DAP) and RTD were collected. RTD was normalised to DAP (RTD/DAP) to compare radiation dose and radiation protection measures. Comparisons were made across procedure categories and individual operators. Results: In 7626 procedures, median and 75th percentile levels were established for operator dose for 8 procedure categories. There was a significant difference in all operator dose measures and DAP across procedure categories (p<0.001). DAP, RTD, and RTD/DAP were significantly different across 22 individual operators (p<0.001). Conclusion: DAP was significantly different across procedure categories and a higher RTD was seen with higher DAP. RTD/DAP can demonstrate radiation protection effectiveness and identified differences between procedures and individual operators with this measure. Procedures and individuals were identified where further optimisation of radiation protection measures may be beneficial. A reference level for operator dose can be created and audited against on a regular basis. Advances in knowledge: This study demonstrates that operator dose can be easily and routinely measured on a case by case basis to investigate dose trends for different procedures. Normalising the operator dose to DAP demonstrates radiation protection effectiveness for the individual operator which can then be optimised as part of an ongoing audit program.

Modification of Filtered Air Intake Flowrate to Improve Control Room Habitability

Control room habitability (CRH) shall be maintained to provide adequate protection for control room operators, such that they can remain in the control room envelope (CRE) safely for an extended period and thus control the nuclear facility during normal and accident conditions. A critical objective of CRH systems is to limit operator doses and/or exposure to toxic gases. The CRH systems does this by the combination of the intake of filtered air, isolation of outside air, recirculation systems and etc. Among the parameters determining radioactivity in a control room (in proportion to radiation doses of operators), intake flowrate of filtered air is an important one. For different types of accident source terms, the evolution of operator doses in a control room versus intake flowrate were analyzed in this paper. It turns out that the increase of intake flowrate results in larger operator doses when inert radioactive gases are the dominant radioactive substances. On the contrary, increasing intake flowrate does good to lower the irradiation level of control room operators when radioactive aerosols dominate the source terms. The rationality behind this fact was interpreted in detail in this paper, with special attention paid to the unfiltered in-leakage rate. It can be inferred that an optimal intake flowrate probably exists leading to the minimum operator dose under an actual accident condition. This paper then performed a calculation analysis based on design parameters and source terms of design basis accident of LOCA (a large break loss of coolant accident) accident. The evolution of operator dose was found to be a U-curve versus increasing intake flowrate, which proved the existence of the abovementioned optimal intake flowrate of filtered air for CRH systems. Furthermore, the sensitivity analysis of intake flowrate was carried out to study the effects of unfiltered in-leakage rate and filtered recirculation. This study indicates that intake flowrate of filtered air can significantly influence the CRH. For different accidents, the intake flowrate should be properly modified rather than set as a fixed value. To optimize the radiological habitability of control rooms, the effects of unfiltered in-leakage must be taken into consideration. Besides, filtered recirculation is an effective way to control radiation exposure caused by iodine and radioactive aerosols.

Radiation exposure, and procedure and fluoroscopy times in endovascular treatment of intracranial aneurysms: a methodological comparison

BackgroundLimited data are available for radiation exposure, and procedure and fluoroscopy times in neuroendovascular treatment (NET) strategies.ObjectiveThis study establishes and compares related parameters between coil embolization (COIL), balloon assisted coil embolization (BAC), stent assisted coil embolization (SAC), and flow diverting technology (FDT) in NET of intracranial aneurysms.Materials and methodsBetween 2010 and 2017, 249 consecutive intracranial aneurysms underwent NET at a single center, all performed by the same operator. Dose area products (DAP), and procedure and fluoroscopy times were recorded and compared between COIL, BAC, SAC, and FDT techniques. Differences in parameters between cohorts were analyzed for significance using the Mann–Whitney U test, unpaired t test and χ2test. Additional subgroup analysis was performed for emergency and elective cases.Results83 aneurysms were treated with COIL (33%), 72 with BAC (29%), 61 with SAC (25%), and 33 with FDT (13%). Baseline characteristics were largely similar within these groups (P>0.05). Among COIL, BAC, and FDT cohorts, no significant difference was found for mean DAP, or procedure and fluoroscopy times (P>0.05). However, compared with all other cohorts, SAC was associated with a significantly higher DAP and longer procedure and fluoroscopy times (P<0.005). No significant difference was recorded for emergency and elective case subgroups.ConclusionCompared with other NET strategies, SAC was associated with a significantly higher DAP, and longer procedure and fluoroscopy times. This study provides an initial dataset regarding radiation exposure, and procedure and fluoroscopy times for common NET, and may assist ALARA (As Low As Reasonably Achievable) principles to reduce radiation risks.